1. Field of the Invention
The present invention relates to a process for the systematic treatment of exhaust gases from municipal refuse incineration plants or other incinerators so as to remove acidic gases and dusts from the exhaust gases.
2. Description of Related Art
As is well known in the art, exhaust gases from municipal refuse incineration plants or other incinerators generally contain acidic gases such as sulfur oxides, hydrogen chloride, nitrogen oxides and the like, and dusts. The treatment of these acidic gases and dusts at one time involves many problems.
The sulfur oxides and hydrogen chloride in the acidic gases can be relatively readily fixed with neutralizing absorbents such as lime, but the nitrogen oxides are not removed.
There is known a process of reducing nitrogen oxides into harmless nitrogen gas in the presence of a denitrating catalyst while introducing ammonia. In this connection, however, when sulfur oxides coexist, side reactions take place, making it difficult to cause the reduction reaction of the nitrogen oxides to selectively proceed. In addition, when dusts deposit on the catalyst, deterioration of the catalyst is inconveniently facilitated.
In order to carry out the removal of dusts, sulfur oxides and nitrogen oxides in separate apparatus, the cost of equipment and the operating cost become huge with a great economical burden.